Could Salicylates Be The Culprit Behind Your IBS Symptoms?

Salicylates are a naturally occuring food chemical found in a range of fruit, vegetables, herbs, nuts and seeds. Some people have an intolerance to salicylates, where eating salicylate-rich food can trigger uncomfortable gut symptoms.

What are salicylates and where are they found?

Salicylates are a type of naturally occurring plant chemical found in a range of plant foods including vegetables, fruit, nuts, spice, wine, coffee and tea. The amount of salicylates present in fruits and vegetables decreases over time as they ripen. Salicylates are important in plants for assisting with growth, photosynthesis, and protecting the plant from pathogens through the production of pathogenesis proteins. The surface of plants and plant foods contains the highest amount of salicylates due to their role in protecting against pathogens and insects. The amount of salicylates present decreases over time with ripening of the plant or fruit. Salicylates also naturally occur in the mint and fruit flavours used to flavour fruit and drinks. They can even be manufactured in products such as food additives and aspirin, which contains the chemical compound acetyl salicylic acid.

Salicylates are different from FODMAPs because they are a type of chemical that originates from salicylic acid, whereas FODMAPs are types of carbohydrates, or sugars, in foods. This means that salicylates are not part of the low FODMAP diet as they are not a carbohydrate. However, you can still be intolerant to salicylates and they may be contributing to your IBS symptoms such as abdominal pain or discomfort, and irregular bowel movements. When a person with a salicylate intolerance consumes a food containing salicylates, the nerve endings in the body are irritated, including the nerve endings in the gut which triggers IBS symptoms.

What are the symptoms of salicylate intolerance?

Salicylate intolerance can trigger a range of symptoms resembling the IBS symptoms triggered by FODMAPs including diarrhoea, inflamed gut, abdominal pain and flatulence. However, they can also trigger other symptoms unlike IBS such as headaches, irritability, asthma, hives, sinus inflammation, nasal congestion and nasal polyps.

Some people have a salicylate intolerance as the salicylate food chemical can trigger a reaction by irritating the nerve endings in the body. Food intolerances are reactions to certain chemicals found in many different foods. In comparison, allergies are a reaction to protein in specific foods. The key difference between allergies and intolerances is that allergies cause a response to the immune system, unlike intolerances. Typical allergic reactions include respiratory issues and hives. Although salicylate intolerance triggers respiratory and skin symptoms that resemble the symptoms of a food allergy, it is actually an intolerance. 

How is salicylate intolerance diagnosed?

Since salicylate intolerance has similar symptoms to a range of allergies, it is important to first rule out the possibility of an allergy. Allergy tests can be arranged by your GP and involve a skin prick test or blood test. Once possible allergies have been ruled out, a diagnostic elimination diet can then be used to determine if you have a salicylate intolerance. The elimination diet has been named as such because it involves eliminating all the possible triggers for symptoms from your diet. The elimination diet is completed for 2-6 weeks, until the symptoms have stopped. This can follow a strict approach, if you are experiencing frequent and severe symptoms, or a simple approach if symptoms are less severe and frequent. It is VITAL to complete the elimination diet under supervision of your dietitian, as they can advise you of which diet is most suitable for you, and what foods you need to restrict. We strongly recommend that you do not complete the elimination diet on your own, but rather under the guidance of a dietitian. This is vital for ensuring that you are not missing any essential foods in your diet and to prevent the misdiagnosis of a food intolerance!

After the symptoms have stopped for at least 5 days, you can begin the challenges. These involve testing trialling salicylates, amines and glutamates in the diet, as these are the food chemicals that can most commonly trigger symptoms from intolerance. Your dietitian will provide guidance through these stages. Once the challenges are completed, your dietitian will inform you of which food chemical/s you have reacted to and provide advice about avoiding them in your diet.

Intolerances vary between people because each individual has their own ‘threshold’ for tolerating the food chemical. Some people will only be able to tolerate a small amount before having a reaction, whereas others can be less sensitive. Regularly consuming these chemicals even in small amounts can cause a build-up in your body if you have an intolerance. You may reach your ‘threshold’ over a period of time, rather than a single meal. This is known as dose-dependence, as the ‘dose’ of the food chemical that you can tolerate determines if you have a reaction and experience symptoms. Your dietitian will assist you with working out your own threshold for food chemicals.

How do I avoid salicylates if I have an intolerance?

The table below shows a range of foods that are high and low in salicylates, and if they are high or low FODMAP foods, to make it easier if you are already on the low FODMAP diet.

	High FODMAP	Low FODMAP
High Salicylate	Vegetables: onion, mushrooms, beetroot, artichoke, cauliflower, corn, spring onion (bulb), kimchi Fruits: apricot, apples (Pink Lady, Granny Smith), sugar bananas (ripe), cherries, peach, cranberries, most dried fruit (currants, sultanas, prunes, dates) Nuts/Seeds: pistachio nuts, coconut flour Legumes:baked beans, fava beans, falafels, textured vegetable protein (TVP) Condiments/Baking: honey Drinks: rum, most fruit juice Meat/seafood: gravy, some processed meats and sausages, marinated meats, canned fish with seasonings added (onion, garlic, herbs, etc.)	Vegetables: broccoli, cucumber, eggplant, capsicum, kale, Asian greens, olives, radish, red chilli, spinach (fresh), zucchini, ginger, most herbs Fruit: pineapple, avocado, red grapes, mandarin, blueberries, orange, kiwifruit, strawberry, rockmelon Nuts/Seeds: Brazil nuts, peanuts, pecans, pine nuts, macadamia nuts, walnuts, sesame seeds, pumpkin seeds, chia seeds, hemp seeds, sunflower seeds Legumes: tempeh Condiments/Baking: extra virgin olive oil, yeast extract spread (Vegemite), vinegars, Worcestershire sauce, turmeric, thyme, tarragon, rosemary, paprika, mustard, asafoetida powder Grains: polenta/cornmeal Drinks: all teas, beer, coffee, wine
Low Salicylate	Vegetables: asparagus, Brussels sprouts, celery, leek, peas, garlic Fruits: pear, apple (Golden & Red Delicious) Nuts/Seeds: cashews Legumes: adzuki beans, black beans, borlotti beans, lima beans, red kidney beans, soy beans, split pea Condiments/Baking: wheat flour, rye flour Grains: rye, wheat Dairy/drinks: milk, soy milk (soy beans), oat milk	Vegetables: green beans, cabbage, carrot, celery, iceberg lettuce, potato, spinach, swede, sweet potato, tomato (fresh), zucchini (peeled) Fruits: banana (firm), papaya/paw paw Nuts/Seeds: poppy seeds Legumes: lentils, firm tofu Condiments/Baking: soy sauce, coriander, golden syrup, maple syrup, brown sugar, white sugar, arrowroot, cacao powder, corn starch, rice flour, tapioca Drinks: rice milk, gin, vodka Grains: oats, rice, rice cereals, buckwheat, konjac noodles, quinoa, sourdough bread, gluten-free flour Dairy: cheddar cheese, cottage cheese, feta cheese, rice milk, soy milk (soy protein), tasty cheese, swiss cheese, Greek yoghurt Meat (plain): beef, chicken, fish, lamb, pork

What other products contain salicylates?

Medications such as aspirin (in the synthetic form acetyl salicylic acid), hair products, mint flavoured toothpaste, perfume, mouthwash and moisturisers can contain salicylates in much higher levels than foods. So it is important to find salicylate free alternatives for these products if you have an intolerance. Products containing manufactured salicylates have much higher levels than the salicylates occurring in foods, so they are more likely to cause an adverse reaction. Your GP and dietitian will be able to assist you with finding low salicylate alternatives for medications.

What if I think I may be salicylate intolerant?

The first step is to contact your GP and dietitian. Your GP will be able to conduct tests to rule out food allergies, while your dietitian will be able to advice if you should complete the elimination diet. Do not attempt the elimination diet without guidance of your dietitian.

Written by: Emily Monro (student dietitian)

Edited by: Rebecca Ponsford (APD)

References:

1. Hanns-Wolf Baenkler: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2696737/
2. Royal Prince Alfred Hospital: http://allergy.net.au/wp-content/uploads/2013/01/Handbook-p1-33.pdf
3. St Joseph’s Health Care London: https://www.sjhc.london.on.ca/sites/default/files/salicylate_free_diet_food_guide.pdf
4. Australasian Society of Clinical Immunology and Allergy: https://www.allergy.org.au/patients/food-other-adverse-reactions/food-intolerance